Cutting Conditions In milling

Valery Marinov, Manufacturing Technology
Milling 111
v Brazed cutters: Very limited number of cutters (mainly face mills) are made with
brazed carbide inserts. This design is largely replaced by mechanically attached cutters.
v Mechanically attached cutters: The vast majority of cutters are in this category. Carbide
inserts are either clamped or pin locked to the body of the milling cutter.
Classification of milling cutters may also be associated with the various milling operations. The figures
below illustrate two of the most important types of milling cutters, end mills and ball-end mills.
Two of the most widely used types of milling cutters with mechanically attached carbide inserts, (Left) end
mills, and (Right) ball-end mills.
Process capabilities and process planning in milling operations
The surface quality and dimensional accuracy achieved in different types of milling depend on the
type of milling operation. For rough cuts, the best surface finish is R a 100~50 µm, while for finishing
cuts much better surface finish of R a 6.3~3.2 µm could be achieved. These values are approximate
and for machining of steel. When cutting gray cast iron or non-ferrous materials, the surface finish
is a grade higher.
The process plan for milling of a single prismatic part includes the following basic steps:
Cut off the stock slightly larger than required;
Cut the basic outside dimensions to size using a milling machine;
Lay out the basic features of the parts (in manual setups, this involves coating the surface
with a blue stain, this is then cut and marked);
Rough cut steps, radii, angles, grooves, etc.;
Lay out the holes to be drilled, and then drill them starting with a center drill and
gradually increasing the drill diameter;
Finish cut part features;
Make internal threads and ream holes if required;
Deburr the finished part.
For mass production, the process plan is significantly changed.